Just to clarify, let's assume that you maintain zone example.be. Let's also say that in .be zone TTL for your NS'es is 86400 and TTL for NS'es in your zone is 345600.
In such scenario the latter will be cached by resolver because it is the authoritative data. For some resolver implementations this behaviour can be overrided. To replace nameserver with new one I would do the following: 1. set up new server; 2. send updates to parent zone; 3. wait for TTL mentioned in my zone (for example above - 345600); 4. shut down old server(s). 2012/6/5 hugo hugoo <hugo...@hotmail.com> > Dear all, > > > > Can anyone clarify to me the use of the TTL for a NS record? > > Let’s take the example of a *.be domain. > > > > A TTL value is present on both locations. > > > > 1) In a dns.be server (for example x.dns.be): in my example here > below, value is 86400 > > 2) In the name server itself: in my example here below, value is 345600 > > > > > If we plan to change the name server to be used for a certain domain, do > we have to change the TTL in the dns.be? > > Is this possible? > > > > Is this value that all the cache servers use? > > If yes…what about the TTL value of the name server itself? > > > > > > Thank in advance of any useful feedback, > > > > Hugo, > > > > > > *Example:* > > > > > > dig @localhost google.be NS +trace > > > > ; <<>> DiG 9.6-ESV-R4 <<>> @localhost google.be NS +trace > > ; (1 server found) > > ;; global options: +cmd > > . 502894 IN NS f.root-servers.net. > > . 502894 IN NS g.root-servers.net. > > . 502894 IN NS h.root-servers.net. > > . 502894 IN NS a.root-servers.net. > > . 502894 IN NS i.root-servers.net. > > . 502894 IN NS b.root-servers.net. > > . 502894 IN NS j.root-servers.net. > > . 502894 IN NS c.root-servers.net. > > . 502894 IN NS k.root-servers.net. > > . 502894 IN NS l.root-servers.net. > > . 502894 IN NS d.root-servers.net. > > . 502894 IN NS m.root-servers.net. > > . 502894 IN NS e.root-servers.net. > > ;; Received 436 bytes from 127.0.0.1#53(127.0.0.1) in 0 ms > > > > be. 172800 IN NS m.ns.dns.be. > > be. 172800 IN NS x.dns.be. > > be. 172800 IN NS london.ns.dns.be. > > be. 172800 IN NS prague.ns.dns.be. > > be. 172800 IN NS brussels.ns.dns.be. > > be. 172800 IN NS amsterdam.ns.dns.be. > > ;; Received 307 bytes from 198.41.0.4#53(a.root-servers.net) in 27 ms > > > > google.be. 86400 IN NS ns2.google.com. > > google.be. 86400 IN NS ns1.google.com. > > google.be. 86400 IN NS ns4.google.com. > > google.be. 86400 IN NS ns3.google.com. > > ;; Received 109 bytes from 193.190.135.4#53(brussels.ns.dns.be) in 1 ms > > > > google.be. 345600 IN NS ns4.google.com. > > google.be. 345600 IN NS ns1.google.com. > > google.be. 345600 IN NS ns3.google.com. > > google.be. 345600 IN NS ns2.google.com. > > ;; Received 173 bytes from 216.239.36.10#53(ns3.google.com) in 18 ms > > > > _______________________________________________ > Please visit https://lists.isc.org/mailman/listinfo/bind-users to > unsubscribe from this list > > bind-users mailing list > bind-users@lists.isc.org > https://lists.isc.org/mailman/listinfo/bind-users > -- AP
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